When the prior art machine is not milking, but still operating, as when preparing cows for the next milking, the milking vacuum is usually shut off at the teat cup ferrule on the claw assembly or in the milk hose and this action permits the air from the atmosphere to apply forces to the inflation to satisfy the vacuum on the other side of the inflation. This causes a ballooning action on the inflation that prematurely wears it due to the excessive stress.
The amount of air admitted inside a teat cup assembly to permit pulsation varies from about two to three cubic feet of air per minute depending upon the rate of pulsation and the capacity of the air chamber between the inflation and the shell. The total air consumed unnecessarily by the shell when the machine is not milking also depends upon the number of units in the barn and the number of units used per man, but it normally may be anticipated that the average milking machine will consume two or three feet of cubic air per minute within the teat cup shells. If this pulsating air were to be shut off, it would increase the total air reserve in the milking system in proportion to the number of units from which the pulsating air is blocked and this would tend to stabilize the vacuum with the milking system and reduce the load on the vacuum pump.
It is also an objective of the present invention to provide an improved milk receiving assembly, improving sanitation between cows, and providing an easy and positive means for shutting off the milking vacuum when the machine is removed from the cow or prior to removal, and in combination with a pulsator vacuum shutoff system.
Another object of the invention is to provide a means by which the milking vacuum will also shut off automatically if the machine becomes accidentally disengaged from the cow during milking and would also prevent excess air intake into the milking unit that will increase chances of milk contamination as well as making the vacuum very unstable.